Synthesis and crystal structure of palladium(II) complexes with 2-[3-(diphenylphosphino)propyl]thiophene

Article abstract of DOI:10.1016/j.poly.2007.05.011

The reaction of 2-[3-(diphenylphosphino)propyl]thiophene (P-S3) with equimolar amount of dichlorobis(benzonitrile)palladium(II) [PdCl₂(PhCN)₂] afforded the binuclear complex trans-[Pd(μ-Cl)Cl(P-S3)]₂ (I) with the P-S3 acting as a monodentate ligand bonded through the phosphorus atom. However, when P-S3 was allowed to react with dichlorobis(benzonitrile)palladium(II) in a 2:1 molar ratio, the monomeric complex trans-[PdCl₂(P-S3)₂] (II) has been isolated. Complex II was also isolated from the reaction of complex I and P-S3 ligand in a 1:2 molar ratio. Complexes I and II and P-S3 were characterized by elemental analysis, ¹H, ¹³C and ³¹P NMR. Single crystal X-ray structures of I and II, which crystallize in the triclinic space group P over(1, ?), have been determined.

Full text of DOI:10.1016/j.poly.2007.05.011

Polyhedron 26 (2007) 4173–4178
www.elsevier.com/locate/poly
Synthesis and crystal structure of palladium(II) complexes
with 2-[3-(diphenylphosphino)propyl]thiophene
a
b
a,
*
Khalifah A. Salmeia , Rawhi H. Al-Far , Hamdallah A. Hodali
a
Department of Chemistry, Faculty of Science, University of Jordan, Amman 11942, Jordan
b
Department of Basic Science, Al-Balqa’ Applied University, Al-Salt, Jordan
Received 8 April 2007; accepted 9 May 2007
Available online 17 May 2007
Abstract
The reaction of 2-[3-(diphenylphosphino)propyl]thiophene (P-S3) with equimolar amount of dichlorobis(benzonitrile)palladium(II)
[PdCl2(PhCN)2] afforded the binuclear complex trans-[Pd(l-Cl)Cl(P-S3)]2 (I) with the P-S3 acting as a monodentate ligand bonded
through the phosphorus atom. However, when P-S3 was allowed to react with dichlorobis(benzonitrile)palladium(II) in a 2:1 molar
ratio, the monomeric complex trans-[PdCl2(P-S3)2] (II) has been isolated. Complex II was also isolated from the reaction of complex
I and P-S3 ligand in a 1:2 molar ratio. Complexes I and II and P-S3 were characterized by elemental analysis, 1H, 13C and 31P
ꢀ
NMR. Single crystal X-ray structures of I and II, which crystallize in the triclinic space group P1, have been determined.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Binuclear complexes; Palladium complexes; Hemilabile ligands; P–S ligands
1. Introduction
Hemilabile ligands combining phosphorus and sulfur
donor sites [8] form stable metal complexes and exhibit
different modes of bonding, depending on the carbon
backbone between the phosphorus and sulfur atoms
and the chemical nature of the sulfur atom [9–11]. In a
previous work, palladium complexes with phosphorus-
sulfur ligands have been prepared and their catalytic
activity towards cyclic olefin polymerization were investi-
gated [12–14].
Herein, we report on the preparation of palladium com-
plexes with the phosphorus–sulfur ligand that combine
tertiary phosphine and thiophene, 2-[3-(diphenylphosph-
ino)propyl]thiophene (P-S3). The palladium complexes
obtained were characterized by 1H, 13C, 31P NMR and sin-
gle crystal X-ray analysis.
Chelating ligands with mixed donors that differ in
their coordination abilities are called hemilabile ligands
[1]. Among the important features of these ligands are
their ability to provide vacant coordination site at the
metal center during reactions and to stabilize reactive
intermediates [2]. With these characteristics, metal com-
plexes having hemilabile ligands have shown improved
catalytic activity in many homogenous catalytic processes
including hydrogenation [3], alternating CO/olefin copo-
lymerization [4] and ring-opening polymerization [5].
Another interesting characteristic of the hemilabile
ligands came from the trans effect resulting from the dif-
ferent donor/acceptor properties of the chelating atoms
which is found to be effective in the control of certain
stereoselective reactions [6,7].
Ph
P
Ph
*
Corresponding author. Tel.: +962
6 5355000/22139; fax: +962
S
65348932.
P-S3
E-mail address: h-hodali@ju.edu.jo (H.A. Hodali).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.05.011

4174
K.A. Salmeia et al. / Polyhedron 26 (2007) 4173–4178
1
2. Experimental
2.1. General
2JC–P = 11.5 Hz, 1C), 28.0 (d, JC–P = 17.0 Hz, 1C), 31.2
3
(d, JC–P = 13.5 Hz, 1C); d: (Cthiophene) 123.2 (s, 1C), 124.5
(s, 1C), 126.8 (s, 1C), 144.6 (s, 1C); d: (Cphenyl) 128.5 (d,
3JC–P = 6.6 Hz, 4C), 128.6 (s, 2C), 132.8 (d, JC–P
=
2
1
All procedures were performed under an atmosphere
of dry, purified nitrogen using standard Schlenk tech-
niques. Solvents were distilled and dried by standard
methods [15]. Thiophene and 1-bromo-3-chloropropane
were purchased from Across. n-Butyllithium (1.55 M
solution in hexane) was purchased from Aldrich. Potas-
sium diphenylphosphide (0.5 M solution in THF) and
palladium(II) chloride were purchased from Fluka. Ben-
zonitrile was purchased from Wardle Chemicals.
[PdCl2(PhCN)2] [16], and 2-(3-chloropropyl)thiophene
[17,18] were prepared as reported. The IR Spectra were
recorded, as KBr discs, on Nicolet Impact-400 FT-IR
spectrometer. The NMR spectra were recorded on a Bru-
ker DPX 300 MHz spectrometer using TMS as internal
reference. The chemical shifts for the 31P NMR spectra
are relative to external H3PO4. Melting points were deter-
mined with Philip-Harris melting point apparatus and are
uncorrected. Elemental analyses were performed by the
Microanalytical Laboratories of AL al-Bayt University,
Jordan.
18.3 Hz, 4C), 138.6 (d, JC–P = 12.5 Hz, 2C). 31P{1H}
NMR (121 MHz, CDCl3): d = ꢀ12.25.
2.2.2. Preparatiom of trans-[Pd(l-Cl)Cl(P-S3)]2 (I)
A sample of P-S3 (0.31 g, 1.0 mmol) in dry benzene
(20 mL) was slowly added to a filtered solution of
[PdCl2(PhCN)2] (0.40 g, 1.0 mmol) in dry benzene
(30 mL). The solution was stirred for 1 h at room temper-
ature. During that time, the solution changed color gradu-
ally from dark brown to orange. Solvent was removed
under reduced pressure till a volume of about 10 mL. Upon
addition of pet. ether (boiling range of 40–60 ꢁC), an
orange precipitate was separated, the product was recrys-
tallized from CH2Cl2/pet. ether, washed with pet. ether
and dried under vacuum at 50 ꢁC. Yield: 0.48 g (92%).
Orange solid; m.p. 225–227 (dec). Selected IR bands
(KBr pellet, cmꢀ1): 3056 (m), 2936 (m), 2896 (m), 1102
(s) (P–Ph). 1H NMR (300 MHz, CDCl3): d = 1.89 (m,
4H, –CH2CH2CH2P–), 2.50 (m, 4H, –CH2P–), 2.87 (t,
J = 7.2 Hz, 4H, –CH2CH2CH2P–), 6.69 (d, J = 2.8 Hz,
2Hthiophene), 6.87 (dd, J = 3.4, 5.1 Hz, 2Hthiophene), 7.07
(d, J = 5.1 Hz, 2Hthiophene), 7.22–7.68 (m, 20H, Hphenyl).
13C NMR (75 MHz, CDCl3): d: (Caliphatic) 25.9 (s, 2C),
2.2. Syntheses
2.2.1. Preparation of 2-[3-(diphenylphosphino)propyl]-
thiophene (P-S3)
1
3
26.5 (d, JC–P = 35.9 Hz, 2C), 30.5 (d, JC–P = 17.5 Hz,
2C); d: (Cthiophene) 123.5 (s, 2C), 124.9 (s, 2C), 126.9 (s,
The compound was prepared following literature proce-
dure [17,18] with modifications. A solution of 2-(3-chloro-
propyl)thiophene (8.0 g, 0.05 mol) in dry THF (50 mL)
was introduced into a 250-mL three-necked round bot-
tomed flask equipped with a nitrogen inlet, dropping fun-
nel, and a condenser that is connected to an oil bubbler.
A solution of potassium diphenylphosphide (100 mL of
0.5 M, 0.05 mol) was then slowly added at ꢀ45 ꢁC. After
the addition was complete, the cooling bath was removed
and the reaction mixture was stirred for 2 h at room temper-
ature. Solvent was completely removed under reduced pres-
sure. The residue was dissolved in diethyl ether (100 mL),
and the ether solution was washed with distilled water
(2 · 100 mL). The ether layer was dried over anhydrous
sodium sulfate over night. After filtration, ether was
removed under reduced pressure, and the thick yellow resi-
due was dissolved in methanol (50 mL). When the solution
was stored at 0 ꢁC a white precipitate was formed. The pre-
cipitate was filtered, washed three times with cold methanol,
and dried under vacuum at room temperature. Yield: 14.3 g
(92%). White powder; m.p. 65–67 ꢁC. Selected IR bands
(KBr pellet, cmꢀ1): 3071 (m), 3050 (m), 2931 (m), 2856
(m), 1120 (s) (P–Ph). 1H NMR (300 MHz, CDCl3):
d = 1.81 (m, 2H, –CH2CH2CH2P–), 2.09 (m, 2H, –CH2P–),
2.94 (t, J = 13.5 Hz, 2H, –CH2CH2CH2P–), 6.75
(d, J = 3.1 Hz, 1Hthiophene), 6.89 (t, J = 4.2 Hz, 1Hthiophene),
7.10 (d, J = 5.0 Hz, 1Hthiophene), 7.31–7.76 (m, 10H, Hphenyl).
13C NMR (75 MHz, CDCl3): d: (Caliphatic) 27.3 (d,
2C), 143.1 (s, 2C); d: (Cphenyl) 127.7 (s, 4C), 128.8 (d,
2
3JC–P = 11.9 Hz, 8C), 131.4 (s, 4C), 133.3 (d, JC–P
=
10.2 Hz, 8C). 31P{1H} NMR (121 MHz, CDCl3):
d = 31.81. Anal. Calc. for [C38H38Cl4P2Pd2S2] (975.34): C,
46.79; H, 3.93; S, 6.57. Found: C, 46.23; H, 3.66; S, 5.51%.
2.2.3. Preparation of trans-[PdCl2(P-S3)2] (II)
A filtered solution of [PdCl2(PhCN)2] (0.40 g, 1.0 mmol)
in dry benzene (30 mL) was slowly added to a sample of P-
S3 (0.78 g, 2.5 mmol) in dry benzene (20 mL). The solution
was stirred for 1 h at room temperature. Solvent was
removed under reduced pressure till a volume of about
10 mL. Upon addition of pet. ether (boiling range of 40–
60 ꢁC), a yellow precipitate was formed. The product
was collected, recrystallized from CH2Cl2/pet. ether
washed with pet. ether and dried under vacuum at 50 ꢁC.
Yield: 0.50 g (60%). Yellow solid; m.p. 143–144 ꢁC.
Selected IR bands (KBr pellet, cmꢀ1): 3081 (m), 3051
(m), 2919 (m), 1431 (s), 1105 (s) (P–Ph). 1H NMR
(300 MHz, CDCl3): d = 1.88 (m, 4H, –CH2CH2CH2P–),
2.50 (m, 4H, –CH2P–), 2.87 (t, J= 7.2 Hz, 4H, –CH2-
CH2CH2P–), 6.68 (d, J= 2.7 Hz, 2Hthiophene), 6.86 (dd,
J = 3.4, 5.1 Hz, 2Hthiophene), 7.07 (dd, J = 1.1, 5.1 Hz,
2Hthiophene), 7.34–7.73 (m, 20H, Hphenyl). 13P{1H} NMR
(121 MHz, CDCl3): d = 17.53. Anal. Calc. for
[C38H38Cl2P2PdS2] (798.04): C, 57.19; H, 4.80; S, 8.04.
Found: C, 57.21; H, 4.79; S, 8.08%.

K.A. Salmeia et al. / Polyhedron 26 (2007) 4173–4178
4175
Table 1
2.3. Reaction of compound I with P-S3
Crystal data for complexes trans-[Pd(l-Cl)Cl(P-S3)]2 (I) and trans-
[PdCl2(P-S3)2] (II)
To an orange solution of I (0.40 g, 0.41 mmol) in dry
CHCl3 (30 mL) was slowly added a solution of P-S3
(0.31 g, 1.0 mmol) in dry CHCl3 (20 mL). The solution
was stirred for 2 h at room temperature. During that time,
the solution changed color gradually from orange to yel-
low. Solvent was removed under reduced pressure till a vol-
ume of about 10 mL. Upon addition of pet. ether (boiling
range of 40–60 ꢁC), a precipitate was separated, washed
with pet. ether and dried under vacuum at 50 ꢁC. The prod-
Parameter
[Pd(l-Cl)Cl(P-S3)]2 (I) [PdCl2(P-S3)2] (II)
Chemical formula
Formula weight
Temperature (K)
C38H38Cl4P2Pd2S2
975.34
293(2)
C38H38Cl2P2PdS2
798.04
293(2)
˚
Wavelength (A)
0.71073
0.71073
Crystal system
Space group
Unit cell dimensions
triclinic
triclinic
ꢀ
ꢀ
P1
P1
˚
a (A)
9.3962(19)
9.954(2)
11.100(2)
84.62(3)
77.96(3)
73.51(3)
972.9(4)
1
7.9828(10)
10.699(2)
10.9374(19)
91.761(17)
105.217(5)
96.463(14)
893.9(3)
1
˚
b (A)
1
˚
uct was characterized by its melting point and H NMR
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
and found to be identical to compound II.
2.4. Crystal structure determination of
trans-[Pd(l-Cl)Cl(P-S3)]2 (I)
3
˚
V (A )
Z
Dcalc (Mg/m3)
1.665
1.483
Absorption coefficient 1.416
(mmꢀ1
F(000)
0.902
A suitable single crystal (yellow platelets) of compound I
was selected for collecting X-ray data. All measurements
were made at 293(2) K using a Bruker/Siemens SMART
)
488
408
Crystal dimensions
(mm)
0.40 · 0.20 · 0.05
0.40 · 0.30 · 0.15
˚
APEX instrument (Mo Ka radiation, k = 0.71073 A)
equipped with a Cryocool NeverIce low temperature
device. Data were measured using omega scans of 0.3ꢁ
per frame for 5 s, and a full sphere of data was collected.
A total of 2400 frames were collected with a final resolution
h Range for data
collection (ꢁ)
Index ranges
1.88–25.25
1.92–25.50
ꢀ11 6 h 6 11,
ꢀ11 6 k 6 11,
ꢀ3 6 l 6 13
14345
ꢀ9 6 h 6 1,
ꢀ12 6 k 6 12,
ꢀ13 6 l 6 13
4081
˚
of 0.83 A. Cell parameters were retrieved using SMART [19]
Reflections collected
software and refined using SAINTPLUS [20] on all observed
reflections. Data reduction and correction for Lp and
decay were performed using the SAINTPLUS software.
Absorption corrections were applied using SADABS [21].
The structure was solved by direct methods and refined
by least squares method on F2 using the SHELXTL program
package [22]. The structure was solved in the space group
Independent reflections 3527 [0.0250]
[Rint
3293 [0.0000]
]
Data/restraints/
parameters
3527/10/224
3318/0/205
Goodness-of-fit on F2
Final R indices
[I > 2r(I)]
1.046
1.068
Ra1 = 0.0268,
wRb2 = 0.0676
R1 = 0.0301,
wR2 = 0.0699
0.543 and ꢀ0.468
R1 = 0.0337,
wR2 = 0.0878
R1 = 0.0393,
wR2 = 0.0915
0.709 and ꢀ0.475
R indices (all data)
ꢀ
P1 ð#2Þ by analysis of systematic absences. All non-hydro-
Largest difference in
peak and hole (e A
gen atoms were refined anisotropically. The thiophene
group was rotationally disordered and refined in two posi-
tions with refined occupancies of 49:51%. Bond lengths and
thermal parameters were loosely restrained. No decompo-
sition was observed during data collection. Details of the
data collection and refinement are given in Table 1. Further
details are provided in the Supporting Information. Hydro-
gen atoms were placed geometrically and refined with a rid-
ing model, with Uiso constrained to be 1.2Ueq of the carrier
atom.
ꢀ3
˚
)
P
P
a
R1 = {|Fo| ꢀ |Fc|}/ |Fo|.
P
P
b
2
wR2 = { [w(Fo ꢀ Fc2)2]/ [w(Fo2)2]}0.5
.
and correction for Lp and decay were performed using
the SHELXTL [22] software. Absorption corrections were
applied using psi scans. Details of the data collection and
refinement are given in Table 1. Further details are pro-
vided in the Supporting Information.
2.5. Crystal structure determination of
trans-[PdCl2(P-S3)2] (II)
3. Results and discussion
3.1. Syntheses
A suitable crystal (yellow parallelopiped) of compound
II was selected, attached to a glass fiber and data were col-
lected at 293(2) K using a syntax diffractometer ‘‘upgraded
to Bruker’s P4 specifications’’ instrument (Mo Ka radia-
The phosphorus–sulfur ligand, 2-[3-(diphenylphosph-
ino)propyl]thiophene (P-S3), was prepared via reaction of
2-(3-chloropropyl)thiophene [17,18] with potassium diphe-
nylphosphide in dry THF. The product was collected and
recrystallized several times from methanol. It was fully
˚
tion, k = 0.71073 A) equipped with a Cryocool NeverIce
low temperature device. Collection and treatment of data
were done similar to compound I with the exception that
cell parameters were retrieved and refined using XSCANS
[23] software on all observed reflections. Data reduction
characterized by its IR, H, 13C and 31P NMR spectros-
1
1
copy. The H NMR spectrum of P-S3 shows, in addition

4176
K.A. Salmeia et al. / Polyhedron 26 (2007) 4173–4178
to the signals due to phenyl protons, two multiplets cen-
tered at d = 1.81 (–CH2CH2CH2P–) and 2.09 (–CH2P–),
and a triplet centered at d = 2.94 (–CH2CH2CH2P–). The
three protons of thiophene appear as two doublets centered
at d = 6.75, 7.10 and a triplet centered at d = 6.89. The 13
C
NMR spectrum of P-S3 shows, d: (Caliphatic) at 27.3 (d, 2JC–P
1
= 11.5 Hz, 1C), 28.0 (d, JC–P = 17.0 Hz, 1C), and 31.2 (d,
3JC–P = 13.5 Hz, 1C); d: (Cthiophene) at 123.2 (s, 1C), 124.5
(s, 1C), 126.8 (s, 1C), and 144.6 (s, 1C); d: (Cphenyl) at
3
128.5 (d, JC–P = 6.6 Hz, 4C), 128.6 (s, 2C), 132.8 (d,
1
2JC–P = 18.3 Hz, 4C), and 138.6 (d, JC–P = 12.5 Hz, 2C).
The above 13C NMR assignment was confirmed by run-
ning Dept-135 experiment that shows, disappearance of
the two quaternary carbons at d = 138.6, and 144.6. The
31P NMR spectrum shows one signal at d = ꢀ12.25.
Reaction of P-S3 with equimolar amount of
[PdCl2(PhCN)2] afforded the binuclear complex trans-
[Pd(l-Cl)Cl(P-S3)]2 (I). Complex I is soluble in acetone,
chloroform, and dichloromethane, and insoluble in diethyl
ether, dioxane, and hexane. Elemental analysis of I for C,
H, and S is consistent with the above formulation. The
1H NMR spectrum of I shows, in addition to the phenyl
proton signals, two multiplets centered at d = 1.89 (–CH2-
CH2CH2P–) and 2.50 (–CH2P–), and a triplet centered at
d = 2.87 (–CH2CH2CH2P–). The signals of the thiophene
protons appear as doublets centered at d = 6.69, and
d = 7.07, and a doublet of doublet centered at d = 6.87.
Compared with the free ligand, the 31P NMR signal of
complex I is downfield shifted to d = 31.81. The 13C
NMR spectrum of I shows, d: (Caliphatic) at 25.9 (s, 2C),
Fig. 1. ORTEP plot of the molecular structure of compound I. Showing
the rotationally disordered of thiophene group. Thermal ellipsoids are
drawn at 50% probability level.
two doublets centered at d = 6.67, 7.06 and a triplet cen-
tered at d = 6.85. The phenyl protons appear as a multiplet
at d = 7.57–7.73. Comparing the 1H NMR spectra of I and
[PdCl2(P-S3)(PPh3)] shows no appreciable differences on
the chemical shift of aliphatic and thiophene protons.
In a similar way, reaction of complex I with P-S3 in a
1:2 molar ratio afforded the monomeric complex,
[PdCl2(P-S3)2] (II), which is characterized by elemental
1
analysis and NMR spectroscopy. The H NMR spectrum
of II shows, in addition to the phenyl proton signals, a mul-
tiplet centered at d = 1.88 (–CH2CH2CH2P–), d = 2.50
(–CH2P–), and a triplet centered at d = 2.87 (–CH2-
CH2CH2P–). The signals of the thiophene protons appear
as a doublet centered at d = 6.68 and two (doublet of dou-
blet) centered at d = 6.86 (J = 3.4, 5.1 Hz) and d = 7.07
1
3
26.5 (d, JC–P = 35.9 Hz, 2C), and 30.5 (d, JC–P
=
1
(J = 1.1, 5.1 Hz). Comparing the H NMR spectrum of I
17.5 Hz, 2C); d: (Cthiophene) at 123.5 (s, 2C), 124.9 (s, 2C),
126.9 (s, 2C), and 143.1 (s, 2C); d: (Cphenyl) at 127.7 (s,
and II shows no appreciable differences in both spectra,
indicating similar mode of bonding for the ligand in both
complexes. The 31P NMR spectrum of II shows one signal
at d = 17.53. The greater downfield shift of the 31P peak
in complex I relative to complex II is attributed to the
increase in Pd–P bond strength, that is trans to bridging
Cl ligand.
3
4C), 128.8 (d, JC–P = 11.9 Hz, 8C), 131.4 (s, 4C), and
2
133.3 (d, JC–P = 10.2 Hz, 8C). Comparing the 13C NMR
spectrum of I with that for the P-S3 ligand shows no differ-
ence on the chemical shift of the thiophene ring carbons,
which is consistent with the ligand being coordinated
through the phosphorus atom only. The 13C NMR signal
for Cphenyl–P was shifted upfield upon coordination with
the palladium metal to 127.7 ppm and appeared as a sin-
glet. Similarly, the signal for CH2–P was shifted upfield
upon coordination with the palladium metal to 26.5 ppm
with an increase in J value (J = 35.9 Hz). The bidentate
mode of bonding for P-S3 seems to be unfavorable with
respect to the formation of the 7-membered chelate ring
and the poor donor ability of thiophene sulfur. In view
of the above data the complex is believed to have a dimeric
structure which was confirmed by single X-ray structure
analysis (Fig. 1).
Complex II was also prepared by the direct reaction of
[PdCl2(PhCN)2] with P-S3 in a 1:2.5 molar ratio. The iso-
1
lated yellow compound was characterized by H and 13C
NMR and found to be identical with an authentic sample
of complex II that has been prepared previously by the
reaction of complex I with P-S3.
3.2. The molecular structure of [Pd(l-Cl)Cl(P-S3)]2 (I)
Yellow platelet-like crystals of I were grown from dou-
ble layer system of CH2Cl2/pet. ether. The solid state
structure was established by X-ray crystallography
(Fig. 1). Selected bond lengths and angles are collected
in Table 2. The two P-S3 ligands bind to the Pd metal
through the phosphorus atoms in a trans position. The
two chlorobridged ligands form with the palladium atoms
a four-membered ring with Cl–Pd–Cl angles of 85.24(3)ꢁ,
and Pd–Cl–Pd angles of 94.76(3)ꢁ. The Pd–Cl bond dis-
As expected, reaction of the chlorobridged palladium
complex I with triphenylphosphine in a 1:2 molar ratio
afforded the monomeric complex, [PdCl2(P-S3)(PPh3)].
1
This complex was characterized by its H NMR spectrum
which shows two multiplets centered at d = 1.89 (–CH2-
CH2CH2P–), 2.52 (–CH2P–) and a triplet centered at
d = 2.85 (–CH2CH2CH2P–). The thiophene protons show

K.A. Salmeia et al. / Polyhedron 26 (2007) 4173–4178
4177
Table 2
˚
Selected bond distances (A) and angles (ꢁ) for trans-[Pd(l-Cl)Cl (P-S3)]2
˚
Bond distances (A)
Bond angles (ꢁ)
Pd(1)–P(1)
Pd(1)–Cl(2)
Pd(1)–Cl(1A)
Pd(1)–Cl(1)
Cl(1)–Pd(1A)
P(1)–C(7)
2.2239(11)
2.2747(11)
2.3081(11)
2.4156(12)
2.3080(11)
1.812(3)
P(1)–Pd(1)–Cl(2)
P(1)–Pd(1)–Cl(1A)
Cl(2)–Pd(1)–Cl(1A)
P(1)–Pd(1)–Cl(1)
Cl(2)–Pd(1)–Cl(1)
Cl(1A)–Pd(1)–Cl(1)
Pd(1A)–Cl(1)–Pd(1)
C(7)–P(1)–C(1)
86.21(4)
96.89(3)
176.89(3)
177.44(2)
91.67(4)
85.24(3)
94.76(3)
104.28(12)
P(1)–C(1)
P(1)–C(13)
1.818(3)
1.823(3)
tance of the terminal chloride is shorter than that of the
bridging chloride. It is interesting to note that, the two
Pd1–Clbridge (Fig. 1) bond distances are different; the
Pd1–Clbridge trans to terminal chloride is shorter than
the one trans to the P-atom. This is consistent with the
higher trans influence of phosphine ligand compared with
Cl. The thiophene ring was rotationally disordered and
refined in two positions with refined occupancies of 50%
(Fig. 2).
Fig. 3. ORTEP plot of the molecular structure of compound II showing
the atom labeling scheme. Thermal ellipsoids are drawn at the 50%
probability level.
Table 3
˚
Selected bond distances (A) and angles (ꢁ) for the complex trans-[PdCl2(P-
3.3. The molecular structure of [PdCl2(P-S3)2] (II)
S3)2] (II)
˚
Bond distances (A)
Bond angles (ꢁ)
Yellow crystals of complex II were grown by slow evap-
oration of CH2Cl2/pet. ether solution at room temperature.
The solid state structure of II is shown in Fig. 3, and
selected bond length and angles are collected in Table 3.
As indicated in Fig. 3, the two P-S3 ligands bind to the
Pd metal atom through their phosphorus atoms in trans
positions. The palladium atom is in the center of the sym-
metry and it displays square planar stereochemistry. The
Pd–P distance in II is longer than that in I, which is consis-
tent with the competition for p-bonding between the trans
phosphorus atoms in II.
P(1)–Pd(1)
Cl(1)–Pd(1)
C(1)–P(1)
C(7)–P(1)
C(13)–P(1)
2.3356(8)
2.2952(9)
1.826(3)
1.819(3)
1.836(3)
Cl(1A)–Pd(1)–Cl(1)
Cl(1)–Pd(1)–P(1)
Cl(1A)–Pd(1)–P(1)
C(1)–P(1)–Pd(1)
C(7)–P(1)–Pd(1)
C(13)–P(1)–Pd(1)
C(1)–P(1)–C(7)
180.00(4)
86.58(3)
93.42(3)
120.76(9)
106.54(9)
115.07(10)
104.14(13)
102.36(14)
106.79(13)
C(1)–P(1)–C(13)
C(7)–P(1)–C(13)
Acknowledgements
We thank Prof. B. Twamley, University of Idaho for the
X-ray structural analysis. We also thank Mr. M.H. Al-Hun-
iti, University of Jordan for obtaining the 31P NMR spectra.
Appendix A. Supplementary material
CCDC 611542 and 632706 contain the supplementary
crystallographic data for I and II. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallo-
graphic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit
@ccdc.cam.ac.uk. Supplementary data associated with this
article can be found, in the online version, at doi:10.1016/
j.poly.2007.05.011.
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